The leading three Premier League teams have all had a go at sitting on top of the table over the last nine days, but Ricardo Carvalho believes it is Chelsea that Manchester United and Arsenal "have to be worried about" after his side reclaimed pride of place on Wednesday night.

Chelsea's 3-0 win over Birmingham City put them back at the top, with a game in hand over their two rivals who meet at the Emirates on Sunday and Carvalho said: "We are playing well but you have to win trophies. We want to be at the top and we want to stay there until the end. The message to the other teams now is they have to be worried about us because we have got great players and we are fit and wanting to help the team to win the trophy."

Chelsea's players are speaking as confidently as they are playing. Seventeen goals in their last four games has revitalised the club after a spell around Christmas that had seen them take six points from a possible 15. No one has benefited more in the past month than Frank Lampard, with five goals in his last four games.

Lampard said Chelsea will go into tomorrow's fixture at Burnley determined to stretch their lead at the top of the league before United and Arsenal meet. "It would be nice to open up a gap," Lampard said. "Those kind of little mental things are great during the season."